The answer is probably Yes.

I wrote a Python program to try to reproduce the above, but due to rounding issues(!!) it gets a longer answer than Randall's. His is correct, 15 yards/s is 7.5 fathoms/sec but my program ends up with an intermediate value of 7.49999mumble and rounds it to 7, adding an extra conversion to 15 m/s in between. https://gist.github.com/jepler/d1a2440469e2228ad50073a3a94c2917

actually, check that -- It may be the case that pint is right in some limited sense. wikipedia thinks that the US fathom is 1.828804 m until 2023; pint uses this definition, so it is correct to round down 15 yards to 7 fathoms. https://en.wikipedia.org/wiki/Fathom#International_fathom

Additionally, without adding furrther units, 45mph is as far as you can go.